1. Field of the Invention
The present invention relates generally to storage libraries for handling and storing media elements such as cartridges and for reading and writing to the media elements using media element players such as drives. More particularly, the present invention relates to a storage library having a free-hanging media element handling robot assembly.
2. Background Art
An automated data storage library generally includes media storage elements such as cartridges, media element players such as drives, and media element handling components such as a media element handling robot assembly. The library includes individual cells which hold respective cartridges. The robot assembly includes a picker which is operable to move about the library and selectively load a cartridge from a cell into a drive. The picker is generally operable to remove cartridges from the cells and drives and load cartridges into the cells and drives.
Certain storage library designs enable the libraries to be expandable for capacity upgrades. Many storage library expansion solutions require complex installation techniques at the library user's site. Some solutions require costly robot assembly duplication, while other solutions require skilled personnel to link existing robot assemblies with the expansion mechanics.
For example, a capacity upgrade may involve adding more storage library modules in a stacked configuration with pass through robotics connecting the individual enclosures of the storage library modules. Other solutions offer a capacity improvement that involve adding additional guide ways (rails) for robot assembly hardware already existing in the storage library. The new guide ways enable the picker to access new slots. In both cases, it is a problem to add capacity to the storage library because additional robot assembly hardware is required. It would be desirable if storage library capacity expansion did not require manipulation, addition, modification, etc., to the robot assembly already part of the storage library.
U.S. Pat. No. 5,870,245 discloses an example of a storage library which suffers from the problem of requiring additional robotics assembly hardware to accommodate capacity upgrades. For example, the disclosed storage library is expandable by inserting additional storage library modules into a rack. Each additional storage library module adds capacity to the storage library by adding more cartridges and/or drives. Each storage library module includes a drive shaft for moving a picker. The rear of the enclosures form a U-shaped channel for receiving a pulley system. The pulley system moves the picker to and from the drive shafts of the storage library modules in order to move the picker assembly amongst the storage library modules. As such, adding additional storage library modules necessitates adding additional robotics assembly hardware. In this case, adding additional drive shafts is needed to accommodate the additional storage library modules.